I design ultra high resolution (10'x20'x300ppi) photo banners mostly. Pretty taxing on the hardware esp for laptops. But portability is essential. That's why I'm worried haha
Anand wrote a great piece reviewing the Sandy Bridge Macbook Pro. And goes into great detail about its operating behaviour and in regards to how that impacts heat and fan noise. You should just read the Anandtech review - it answers most questions about this.
This NEXT die shrink is from 32nm to 22nm and therefore represents a significant jump. It will result in some of the gain being given in performance. And some gain being given as power savings. Per the same workload.
Intel Ivy Bridge TDPs aren't going to be directly comparable to Sandy Bridge TDPs. Thats not speculaton, but information reported by press who have attended Intel presentations about Ivy Bridge during the last 12 months. The architectures are similar, but aren't directly comparable. The 3D transistors is very different. In fact, Anandtech have another great article just solely talking about that one thing.
But even accounting all those Ivy Bridge changes, thats not the full story. Since in the Macbook Pro CPU accounts for only about half of the total 60-80W power draw (from AC power brick) when plugged in. Its the discrete GPU which accounts for much of the remaining 50%. Its probably 20-30 Watts or so. A little more if you have chosen to overclock the graphics.
Current GPUs are 40nm. Well, the 2012 GPU process shrink is from both vendors this year. And will replace all the current 40nm GPUs with brand new 28nm GPUs. Unfortunately there are no solid rumors whatsoever yet about such GPUs being incorporated into the very first Ivy Bridge Macs. There ARE reported yield difficulties / slow ramp up at both of the chip foundries for many / most 28nm designs.
Anyway the bottom line is that only upto half total system power savings can possibly ever come from the Ivy Bridge CPU. And the other approx half mostly depends on a newer 28nm mobile GPU being present on same said logic board. That would all be a noticeable improvement over any of today's available tech.
It just remains to be seen WHEN in 2012. If we are lucky enough to get new GPUs, the timing and availability may be "approximately" in sync with the release of Ivy Bridge. Give or take a couple of months. April-May-June-July-August is actually FOUR whole months. So its a real, bona-fide possibility. Or NOT, then the graphics will come in the next refresh (a late 2012 refresh).